Method of making finned tubing



Aprii 23, 1929. H. w. BUNDY METHOD OF MAKING FINNED TUBING Filed July 5, 1927 INVENTOR.

Harry W Bur/641x I 'Ef ATTORNEY.

Patented Apr. 23, 1929'.

UNlTED STATES HARRY W. BUNDY, 01 DETROIT, MICHIGAN.

marital) or MAKING FINNED TUBING.

Application filed July 5,

This invention relates to a method .of makin finned tubing and it has to do more especizfily with the method of applying fins to a pre-formed tube. The inventioif contemplates a method wherein fins can be applied to a tube which is traveling with continuous longitudinal movement. The method therefor is nicely adapted for use in conjunction with the making of tubing from stock which is rolled transversely into tube form while moving longitudinally.

In the accompanying drawings: Fi 1 is a diagrammatical'assembly view showing the final .rollers of a tube forming mechanism and showing how the fin stock is applied to the pre-formed tube.

Fig. 2 is an enlarged side elevation of a die for shaping the fin stock. a Fig. 3 is a sectional view on line 33 of Fi 2. a F Fig. 4 is a sectional view on line 4-4 of Fig. 5 is an end elevational view of the fin applying device viewed on line 5-5 of Fig. -1. Fi 6 is a side view of a portion of the comp eted tubing.

' Fig. 7 s a sectional'view of the tubing shown in Fig. 6.

Fi 8 isa view similar to Fig. 5 showlng the n applying mechanism, but showing, however, the modified form.

Fig. 9 is'a side view of a, portion of tubing made by the modified form of device shown in Fig. 8..

Fig. 10 is a sectional view taken through the tube shown in Fig. 9. In Fig. 1 a completed tube is shown at 1, and the tube is passing through the last forming rollers of a tube forming machine. These rollers are referenced 2. The manner in which a tube is formed from that strip stock by the use of forming rollers which roll the stock transversely is well known to those versed in the art, and sucha machine forms no part of the present invention and need not be further described. Asithe tube moves forward from the forming mechanism the fin stock is applied. For this purpose a rotating frame 5 is provided. This frame is supported by a suitable standard 6 and it is carried by a rotating hollow shaft 7 which may be turned by means of a belt not shown) running over the pulley 8. The rame "5 is pinned to the shaft, as shown 1927. Serial No. 203,382.

at 9. The shaft 7 being hollow permits the tube to pass therethrough. The rotating frame carries sup lies of fin stock which is preferably in the orm of'spools, as shown at 10. For the purpose of convenience of disclosure, but two spools of fin stock are shown in Fig. 1. However, a greater number can be used, and it is thought preferable to use four supplies of stock, as will be seen in Fig, 5. The frame carries rollers 11, and the fin stock, which is fiat in form, when upon the spools is drawn over the rollers, as clearly shown in Fig. 1.

Fixed to the frame so as to rotate therewith is a die 12 which is apertured to permit the passage of the tube therethrouglh, as shown at 13. This die is provided with slots or grooves through which the strip stock of the fins is drawn. Near the entrance of the stock into the die the grooves are shaped substantially as shown in Fig. 3, but they gradually change into U shape, as shown in Fig. 4. Thus as the stock is drawn through the die is it formed into U shape in cross section. This provides for the shaping of each strip of stock into U shape and forms the U shaped fins 13, as viewed in Fig. 7.

As the tube moves longitudinally through theframe 5, the same is rotated and the stock is spirally wound upon the tube, being drawn from the supply rolls. The tube then passes with continuous movement through a suitable furnace 15.which heats the tube and the fins. The stock which forms the fins may be tinned so that when the tube is heated in the furnace the fins are sweated to the tube so as to be securely soldered thereto. The tube with the fins thus applied may then be given a solder bath by passing through a suitable solder elevating and ouring device 16 which lifts molten solder rom a tank 17 and pours the same over the tube. However, the fin stock may not be tinned but may. be secured to the tube by the application of solder in the bath 16. As the tube moves formu ward the excess solder may be blown off by air coming through the nozzle 18, and then the tube may be cooled by a'water bath as repre-' sented at 19. Finally, the tube is cut in suitable lengths by either a-hand operated or au- 105 tomatic cut-off device 20. r

When but two supplies offin stock are used, as shown in Fig. 1, or when four supplies are used, as indicated in Fig. 5, is it thought pref- 'erable to shape the stock so that it is U shaped no in cross section as above described. However, a. greater number of supplies of fin stock can be used, and in Fig. 8 is showna rotating frame 5 provided with six projecting arms and each carrying a roll of stock 10. With this form the die 12 is such as to give the stock an angular form in cross section, or L-s'hape, thus forming fins 14, as shown in Fig. 10.

With the U shaped fin, each strip of stock in reality forms two fins which are secured to the tube at thebight portion of the U. With the L shaped fin, one strip of stock forms but one fin, and one leg of the L is secured to the tube.

In practicing the method, the fin stock is spirally Wound on thetube under tension so that in the space which intervenes between the winding die and the furnace there is no tendency for the fins to sag or fall away from thetube because the tension holds the fins be noted that the fin stock is wound on'the tube with rather a gradual spiral; thus it is not necessary to crimp or corrugatethe stock because the metal can be drawn or stretched sufiiciently to wind it around the tube without crimping or corrugating.

While the inventionis adaptable for use in association with the tube forming mechanism, and has been so described, the invention is not limited to such use. In other words, tubing can be made up in lengths and laid aside or stored and the fins can be applied thereto at any time by taking a length of tubing and running it through the fin applying mechanism. The use of fins of different shape and cross section can be varied as desired, so that tubing which is to be put to various uses can be made in the best manner for such use. l

I am aware that it has been proposed to apply fin stock to a-tube by feeding the fin stock toward the tube transversely to the longitudinal movement of the tube and ro-' tating the tube While it is moving longitudinally. This involves the necessity of rotating the tube and also crimping or corrugating the stock. The present invention departs from this method inthat the stock is held on a roller, the axis of which is transverse to the length of the tube, and the stock is fed to the tube in adirection which approaches the direction of the longitudinal movement of the tube. The tube is held againstrotation, whereas, the fin stock is rotated and thespeed of movement of the tube and the speed of rotation of the frame holding the supplies of fin stock are so coordinated that the fin stock is tightly wound upon the .tube under tension. The shaping of the stock into U form, or angle form, provides a relatively large surface of contact between the tube and the fin.

This aids in providing a secure connection between the fin and the tube, and furtherwhich consists in moving a tube longitudinally, holdingthe tube against rotation while so moving, maintaining a supply of flat fin stock at one side of the tube, feeding the fin stock to the tube in the direction of the longitudinal movement of the tube, and rotating the supply of the fin stock around the tube to wind the fin stock on the tube.

2. The method of making finned tubing which consists in moving a tube longitudinally, holding the tube against rotation while so moving, maintaining one or more spoolsof flat strip fin stock, each of Which is located at one side of the tube and disposed on an axis transverse to the axis of the tube, feeding the fin stock to the tube, and rotating the supplies of fin stock around the tube to spirally wind the stock on the tube.

3. The method of making finned tubing which consists in movinga tube longitudinally, holding the tube against rotation while so moving, maintaining one or more spools of fin stock, 'each of which is located at one side of the tube and disposed on an axis transverse to the axis of the tube, feeding the fin stock to the tube in the direction of the longitudinal movement of the tube, and rotating the supplies of fin stock around the tube to spirally wind the stock on the tube.

4. The method of making finned tubing, which consists in moving a tube longitudinally, holding the tube against rotation while so moving, maintaining a supply of flat. fin stock at one side of the tube, feeding the fin stock to the tube in the general direction of the longitudinal movement of the tube, bending the flat stock so that it is angle form in cross section, rotating the supply of stock around the tube to spirally wind the stock on the tube with one portion of the angle forming a relatively wide contact with the-tube.

5. The method of making finned tubin which consists in moving a tube longitudinally;holding' the tube against rotation while so moving, maintaining a su ply of fin stock at the side of the tube, feedlng the fin stock to the tube, bending the flat fin stock into U shape in cross section, and then rotating the supply of fin stock around the tube to spirally wind the stock on the tube with the on a tube with the bight portion of the U contacting with the tube,' andwith a single strip of stock in reality forming a pair of spiral fins. Y

bight portion of the U contacting directly L stock on 7. The method of making finned tubing, which consists in moving atube longitudinally through a battery of rolls of fin stock, each having it axis extending transverse to the movement of the tube,-holding the tube against rotation while so moving, feeding the stock on the rolls to the tube in" the general direction of the movement of the tube, bending the stock so that it is angular in cross section, and rotating the battery of rolls of fin stock around the tube to spirally wind the stock on the tube with one portion of the angle forming a relatively large contact with the tube.

' 8. The method of making finned tubing,-

whi'ch consists in moving a tube longitudinally through a battery of rolls of fin stock, each having its axis extending transverse to the movement of the tube, holding the tube against rotation while so moving, feeding the the rolls to the tube in the general direction of the movement of the tube, bending the stock so that it is U shaped in cross section having a relatively flat bight portion to the U, and rotating the rolls around the tube to wind the U shaped stock on the tube with the bight portion of the U contacting directly'against the tube.

9. The method of making finned tubing which consists in moving a tube longitudinally, holding the tube against rotation While rotating a supply of fin stock around the tube, tube so that the stock is spirally wound on the tube, and coordinating the relative speeds of longitudinal movement of the tube and the rotation of the stock around the tube so that the spiral of the fin stock is of a pitch such as to permit winding of the stock around the P tubelby drawing or stretching the metal of I the fin stock.

10. The method of making finned tubing which consists in moving a tube longitudis nally, holding the tube against rotation while so moving, rotating a supply of fin stock feeding the fin stock to-the around the tube, feeding the fin stock to the tube. so that the stock is spirall wound on.

the tube and coordinating the re ative speeds of longitudinal movement of the tube and the rotation of the stock around the tube so that the spiral of the fin stock is of such a gradual nature thatcrimping or corrugatingof the stock is unnecessary.

11. The method of making finned tubing which consists in moving atube longitudinally, holding the tube against rotation while so moving, maintaining a supply of fin stock at one side of the tube, feeding the fin stock to the tube'in the direction of the longitudinal movement of the tube, and rotating the suppklly of the fin stock around the tube to wind t e the fin stock to the tube.

12. The method of making finned tubing which consists in moving a tube longitudinally, holding the tube against rotation while so moving, maintaining a su ply of fin stock -1 at one side of the tube, feedlng the fin stock to the tube in the direction of the longitudinal movement of the tube, and rotating the sup-' ply of the fin stock around the tube to wind the fin stock on the tube, passing the tube fin stock on the tube, and then securing through a solder bath to secure the fin stock" to the tube, removing excess solder, cooling the tube and then severing the tube into lengths. t

13. The method of making finned tubing which consists in moving a tube longitudil y, so moving, maintaining a su ply of fin stock at one side of the tube, feeding the fin stock holding the tube against rotation whileto the tube in the direction of the longitudinal movement of the tube, and rotating the suply' of the fin stock around the tube to wind the fin stock on the tube,and then applying mrlglten metalto secure the finstock to the tu e.

In testimony whereof I aflix my signature.

HARRY w. BUNbY. 

